How to deploy Node.js Applications with pm2 and Nginx on Ubuntu

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pm2 is a process manager for Node.js applications, it allows you to keep your apps alive and has a built-in load balancer. It's simple and powerful, you can always restart or reload your node application with zero downtime and it allows you to create a cluster of your node app.

In this tutorial, I will show you how to install and configure pm2 for the simple 'Express' application and then configure Nginx as a reverse proxy for the node application that is running under pm2.

Prerequisites

Ubuntu 16.04 - 64bit

Root Privileges

Step 1 - Install Node.js LTS

In this tutorial, we will start our project from scratch. First, we need Nodejs installed on the server. I will use the Nodejs LTS version 6.x which can be installed from the nodesource repository.

Install the package 'python-software-properties' from the Ubuntu repository and then add the 'nodesource' Nodejs repository.

Step 2 - Generate Express Sample App

I will use simple web application skeleton generated with a package named 'express-generator' for this example installation. Express-generator can be installed with the npm command.

Install 'express-generator' with npm:

npm install express-generator -g

-g: install package inside the system

We will run the application as a normal user, not a root or super user. So we need to create a new user first.

Create a new user, I name mine 'yume':

useradd -m -s /bin/bash yumepasswd yume

Login to the new user by using su:

su - yume

Next, generate a new simple web application with the express command:

express hakase-app

The command will create new project directory 'hakase-app'.

Go to the project directory and install all dependencies needed by the app.

cd hakase-appnpm install

Then test and start a new simple application with the command below:

DEBUG=myapp:* npm start

By default, our express application will run on port 3000. Now visit server IP address: 192.168.33.10:3000

The simple web application skeleton is running on port 3000, under user 'yume'.

Step 3 - Install pm2

pm2 is a node package and can be installed with the npm command. So let's install it with npm (with root privileges, when you are still logged in as user hakase, then run the command "exit" ro become root again):

npm install pm2 -g

Now we can use pm2 for our web application.

Go to the app directory 'hakase-app':

su - hakasecd ~/hakase-app/

There you can find a file named 'package.json', display its content with the cat command.

cat package.json

You can see the 'start' line contains a command that is used by Nodejs to start the express application. This command we will use with the pm2 process manager.

Run the express application with the pm2 command below:

pm2 start ./bin/www

Now you can see the results is below:

Our express application is running under pm2 with name 'www', id '0'. You can get more details about the application running under pm2 with the show option 'show nodeid|name'.

pm2 show www

If you like to see the log of our application, you can use the logs option. It's just access and error log and you can see the HTTP Status of the application.

pm2 logs www

You can see that our process is running. Now, let's enable it to start at boot time.

pm2 startup systemd

systemd: Ubuntu 16 is using systemd.

You will get a message for running a command as root. Back to the root privileges with "exit" and then run that command.